refactor: evaluator incomplete.

SO, i forgot to implement nud and led correctly and the parser cant tell
apart from - as unary and - as binary (+ as well), i need to correct
that, move Node * to TreeResult so to use NodeResult with nud and led

include/parser.h

@@ -37,6 +37,7 @@ typedef enum {
     PARSER_MISSING_OPERAND,
     PARSER_UNMATCHED_PAREN,
     PARSER_OUT_OF_MEMORY,
+    PARSER_INVALID_TOKENIZE,
 } ParserErr;
 
 typedef struct {